M87.863
BillableOther osteonecrosis, unspecified tibia
Last updated: FY2026 ICD-10-CM (Oct 1, 2025 – Sep 30, 2026) | CMS-HCC V28 (100% phase-in, PY2026)
Is M87.863 an HCC code?
Yes. M87.863 maps to Bone/Joint/Muscle Infections/Necrosis under the CMS-HCC V28 risk adjustment model (and Bone/Joint/Muscle Infections/Necrosis under V24).
HCC Category Mapping
RAF weights shown are the community, non-dual, aged base weights from the CMS risk adjustment model file. Actual per-patient RAF contribution depends on member segment, interactions, and the model year used by the payer. V28 is the CMS-HCC model phased in over payment years 2024–2026; V24 remains in use during the transition and for historical data.
MEAT Criteria for M87.863
For M87.863 to count as a valid HCC diagnosis in a given encounter, the provider's documentation must show MEAT: Monitor, Evaluate, Assess, or Treat. A diagnosis from a prior year does not carry forward automatically — it has to be re-documented and supported each calendar year.
- MMonitor: signs, symptoms, disease progression, or lab trending documented in the note
- EEvaluate: test results, medication response, or physical findings reviewed by the provider
- AAssess: explicit mention in the assessment or plan with acknowledgment of status
- TTreat: medication, referral, procedure, therapy, or counseling tied to the diagnosis
Only one of M/E/A/T is required to support the code, but the documentation must be specific enough to show that the provider actually addressed M87.863 during that encounter — not just copy-forwarded from a problem list.
What This Code Means
M87.863 is the ICD-10-CM diagnosis code for other osteonecrosis, unspecified tibia. Death of bone tissue in the tibia (shin bone) when the specific side is not documented or applies to both sides. M87.863 sits in the ICD-10-CM chapter for diseases of the musculoskeletal system and connective tissue (m00-m99), within the section covering other osteopathies (m86-m90).
Under the CMS-HCC V28 risk adjustment model, M87.863 maps to Bone/Joint/Muscle Infections/Necrosis (HCC 92) with a community, non-dual, aged base RAF weight of 0.209. Under the older V24 model, M87.863 mapped to the same category but with a base RAF weight of 0.482 — V28 recalibrated weights across the entire model. V28 is the CMS-HCC risk adjustment model that reached 100% phase-in for payment year 2026, replacing V24 which was used during the PY2024–PY2025 transition.
Use this code only when laterality cannot be determined from documentation. Because M87.863 maps to a payment HCC, the provider's documentation must satisfy MEAT criteria (Monitor, Evaluate, Assess, or Treat) for the encounter to count toward the patient's Medicare Advantage risk adjustment score. When documentation is ambiguous, coders should issue a provider query rather than assume the highest-specificity variant.
HCC Buddy maintains structured V28 and V24 mapping, RAF weights, and MEAT documentation criteria for M87.863 sourced directly from the CMS-HCC risk adjustment model files and the CMS ICD-10-CM code set.
Coding Tips
Clinical Significance
Unspecified tibial osteonecrosis represents chronic bone death requiring comprehensive management to prevent complications and preserve limb function. The unspecified nature may indicate bilateral involvement or insufficient documentation of laterality.
Documentation Requirements
- ✓Documentation of tibial involvement without specific laterality
- ✓Imaging evidence confirming osteonecrosis (X-ray, MRI, or bone scan)
- ✓Clear exclusion of traumatic, infectious, or radiation-related causes
- ✓Assessment of bilateral involvement if applicable
- ✓Pain and functional status evaluation
- ✓Risk factor identification and management
- ✓Treatment response monitoring
- ✓Prognosis and long-term care planning